The man who has won millions of hearts as Captain Jack Harkness in Torchwood often finds some genuine eye-openers in his mailbag.
John, 44, said: “Sometimes I get sent knickers and occasionally I get requests to send some of my own underwear back. I always politely decline. It’s not going to happen.
“I get sent some seriously raunchy photographs too. They really don’t hold back, some of these women. The photographs are filthy but they’re not really my thing to be honest.
“All I’ll say is I appreciate the loyalty. So thank you.
“But it’s not really for me. I usually show them to my driver, who’ll make some noise like ‘phwoar’. I do get some really nice letters too.”
The handsome star has become a much-loved fixture on screens – in high-octane sci-fi drama Torchwood and kicking off BBC1’s Saturday night offerings on the dream-come-true show Tonight’s the Night.
His popular appeal has made his face one of the most recognisable on TV. Tonight’s the Night has proved a roaring success, Torchwood has moved from a cult hit to a mainstream classic. But the performer who can sing, dance, act and present still finds it hard to explain his popularity.
He said: “For some reason I seem to be a massive hit with middle-aged women. I seriously don’t know what it is.
“I wish I could bottle up the formula for people because you could have a lot of fun with it.
“I don’t know if they just trust me and see me as their gay best friend.
“I think my biggest appeal for fans is probably the fact that I’m honest. I’m up front about who I am. I’m a little naughty. I have a naughty side and everybody knows that. But I know when to use that and when not to.
“People love to laugh. I make them laugh. I don’t know what it is about me and women. If they think I’m their gay best friend that’s fantastic. Everyone should have a gay best friend.”
The West End stage star has a new album out later this year.
And Torchwood is such a success in the US that its budget is in excess of £1million per episode, thanks to a joint production deal with a large North American cable network.
Riding on the crest of a wave, John clearly enjoys his celebrity. He said: “It annoys me when some moan about the fame that comes with being on TV.
“It’s the best job in the world and I love everything about it. I’m not ashamed of that.
“If being a celebrity comes with that, I’m totally up for that. My partner Scott said to me one day, ‘What have you been up to?’ I replied, ‘Well it was fantastic, this morning I blew up a spaceship and fired a machine gun from a Land Rover as I drove across the beach chased by a helicopter.
“Then I went off and had sex with a 22-year-old. It’s a bit of a cliché but it really is the best job in the world.”
John beams with pride as he mentions Scott, the love of his life since their chance meeting at a theatre stage door at the age of 27.
The pair became civil partners in December 2006. John’s Torchwood co-stars, including Eve Myles, were guests.
John said: “We have been together 17 years. He’s an architect. We met when I was in a play. I performed totally naked but when we met at the stage door later it was me that was nervous.
“From the very first time I saw him I knew he was the one, although to be totally honest I held back for a while because I thought he might think I was a lot younger than I am.
“It was a year later I actually plucked up the courage to ask him out. And on the same day Cher asked me out for dinner. She’d seen me in Sunset Boulevard and decided to get in touch.
You don’t say no to Cher so I wouldn’t have said no normally. But I’d waited so long for my first date with Scott I told her I couldn’t make it.
“She just laughed and said, ‘Oh, just bring him along.’ So Scott and I went together. It was a very different first date.”
The evening sparked rumours that John had become Cher’s toyboy lover. They were spotted leaving a restaurant together.
He recalled: “It was a ridiculous rumour but it was a lovely night with Cher.
“Obviously what people didn’t know was that I was in love with the guy just a few paces behind me.”
John’s passionate and open attitude towards his sexuality has made him a prominent figure in the gay community,
He was invited to a reception at 10 Downing Street last year to meet David Cameron and his deputy Nick Clegg.
Far from being overawed by his powerful hosts, the strong-minded star quickly made his feelings clear, telling ministers he voted Labour at the last election.
John said after the meeting: “They asked me if I could liaise with them about things that may affect the gay and lesbian community to ensure they were making the right decisions. I immediately perked up and thought they seemed really interested.
“They said to me that I must have voted for them because I turned up. But I told them that actually I didn’t. There was a gentleman there who rolled his eyes at that.
“I told him that was exactly the reason I didn’t vote for them, because of that sort of attitude in politics.
“The Conservatives are good at big business but it’s not about me making money.”
It is a glimmer of John’s serious side, rarely seen during his ultra-energetic TV performances and larger-than-life stage shows.”
Despite his seemingly limitless energy he is not the “party animal” he once was.
When we met at 9am in a BBC dressing room her said: “It’s a bit early for me. I’ve toned things down lately.
“I can’t handle clubs and wild nights out like I did in my 20s. I’m lively when I perform and I always put everything into a show but when I get home I love lying down in front of the TV and relaxing.
“I’m not quite the party animal people imagine. I’m certainly not a big fan of night clubs. But that doesn’t mean I don’t enjoy a vodka and tonic or two after a tough day.”
JOHN Barrowman stars in Torchwood, 9pm Thursday, and hosts Tonight’s the Night, 6.45pm Saturday, both on BBC1.
BONUS BARROWMAN: New pics of John and Scott tweeted yesterday